使用 Jsoup 解析 nodeList 值

Question

http://www.smbs.biz/ExRate/StdExRate.jsp

In this Website, I tried to parse the value of the table for the currency.

The below value in the table is the value I want to extract.

In developer tool, I can see the value only in 'Elements' window, not in 'source' window. I guess the data is called when using ajax? How can I extract the data using Jsoup?

Here's the code I was trying to parse the code, which failed:

try {
          doc = Jsoup.connect("http://www.smbs.biz/ExRate/StdExRate.jsp").get();
       } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
       }
       //Elements exchangeRateElement = doc.select(".brb0 td:nth-child(3)").eq(1);           
       Element exchangeRateElement = doc.getElementsByClass("brb0").get(10);

       String cur=null;

       for (Node node : doc.childNodes()) {
        System.out.println("node : "+node);
         if (node instanceof TextNode) {
            cur = ((TextNode) node).getWholeText();
            cur = ((TextNode) node).text();
             break;
         }
     }

Answer 1

When we load the page in a browser with disabled JavaScript, we note, that the table remains empty.

Activating JavaScript and monitoring the network tab (chrome dev tools/F12) on a reload, we see a request:

http://www.smbs.biz/ExRate/StdExRate_xml.jsp?arr_value=USD_2016-09-13_2016-10-05

And the response contains a chart with the needed information:

<chart 
    [...]   
    <set color='c93749' label='16.09.13' value='1110.6' />
    <set color='c93749' label='16.09.19' value='1112.3' />
    [...]
    <set color='c93749' label='16.10.04' value='1102' />
    <set color='c93749' label='16.10.05' value='1105.1' />
    <styles>
        [...]
    </styles>
</chart>

Before we request the chart we need to grab the JSESSION cookie and add it to the request.

Example Code

String userAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36";

try {
    // response needed to grab the cookies: res.cookies()
    Response res = Jsoup.connect("http://www.smbs.biz/ExRate/StdExRate.jsp")..timeout(10000)
            .userAgent(userAgent).method(Method.GET).header("Host", "www.smbs.biz").execute();

    Document doc = res.parse();

    String startDate = doc.getElementById("startDate").attr("value").replace(".", "-");
    String endDate = doc.getElementById("endDate").attr("value").replace(".", "-");

    doc = Jsoup.connect("http://www.smbs.biz/ExRate/StdExRate_xml.jsp?arr_value=USD_" + startDate+"_" + endDate)
            .userAgent(userAgent).timeout(10000).header("Host", "www.smbs.biz").cookies(res.cookies())
            .header("Connection", "keep-alive").method(Method.GET)
            .referrer("http://www.smbs.biz/ExRate/StdExRate.jsp").get();

    Elements elements = doc.select("chart > set");

    for (Element element : elements) {
        System.out.println(element.attr("label") + ": " + element.attr("value"));
    }

    Element currentRateElement = doc.select("chart > set").last();

    System.out.println("Current rate for " + currentRateElement.attr("label") + ": " + currentRateElement.attr("value"));

} catch (IOException e) {
    e.printStackTrace();
}

Output

16.09.13: 1110.6
16.09.19: 1112.3
16.09.20: 1120
16.09.21: 1119.5
16.09.22: 1116.8
16.09.23: 1103.1
16.09.26: 1104.2
16.09.27: 1106.9
16.09.28: 1103.5
16.09.29: 1095.7
16.09.30: 1096.3
16.10.04: 1102
16.10.05: 1105.1
Current rate for 16.10.05: 1105.1